Synchronous Isolated Cystic Pancreatic Metastasis Arising From Primary Colorectal Cancer: A Rare Case Report

BACKGROUND Pancreatic cancer ranks twelfth in incidence and sixth among the leading causes of cancer-related death worldwide. Most pancreatic cancers are primary adenocarcinomas, whereas metastatic tumors are rare, representing 1% to 2% of cases. Renal cell carcinoma is the most common source of pancreatic metastases, followed by less frequent origins such as the stomach, colon, lung, and breast. However, pancreatic metastases from colorectal cancer are exceedingly rare; their clinical behavior, management, and prognosis remain unclear. We report a case of pancreatic metastasis from colorectal cancer, including management details that may improve understanding and guide future care. CASE REPORT A 70-year-old man presented with bleeding from the rectum and a change in bowel habits. Colonoscopy and biopsy confirmed rectal adenocarcinoma. Staging revealed a 5-cm cystic pancreatic lesion; further evaluation with endoscopic ultrasound and fine-needle aspiration confirmed metastatic rectal adenocarcinoma. The patient received pelvic radiation and chemotherapy, followed by abdominoperineal resection. After recovery, additional chemotherapy was administered for suspected local progression of the pancreatic metastasis. Restaging demonstrated stable disease without other metastases, and the patient underwent a classical Whipple procedure. Histopathological analysis confirmed metastatic colorectal adenocarcinoma with mucinous features, vascular and perineural invasion, and negative margins. CONCLUSIONS Although studies of secondary pancreatic cancer are limited, surgical resection remains the cornerstone of treatment, irrespective of tumor origin; it is associated with improved palliation and more favorable survival outcomes.